Many patients with cystic fibrosis (CF) require large doses of enteric coated (EC) pancreatic enzymes to control steatorrhea. High doses of EC enzymes were associated with fibrosing colonopathy. A major reason that CF patients require large doses of EC enzymes is acidity in the duodenum which is not favorable to maximal activity of lipase. A new and innovative EC enzyme recently was introduced to the market. This new product, Pancrecarb, contains bicarbonate which, theoretically, increases duodenal pH and decreases steatorrhea with lower doses. No studies have compared Parcrecarb to EC enzymes (without bicarbonate) in reducing steatorrhea in well controlled, metabolic balance studies. Such studies would allow the lowest enzyme doses, maximum safety and minimum costs. This study will (1) compare the effectiveness of Pancrecarb vs. the patient's usual EC enzyme (without bicarbonate) in decreasing steatorrhea in CF studies. Twenty-four subjects will be evaluated in the total study at two different sites; twelve at the IUMC General Clinical Research Center and twelve at the second site. A crossover design will randomly assign Pancrecarb or the patient's usual EC enzyme to either of two consecutive 7 day treatment periods. Enzymes from a single batch will be analyzed and the same lipase doses will be given during both treatment periods. Weighed diets and stool markers will be used during both treatment periods. Pancrecarb is expected to decrease steatorrhea better than EC enzymes without bicarbonate.